Durabilité de l’adhésion entre métaux et polymères^*

Durability of adhesion between metals and polymers

IFAM. Brême-Lésum (R.F.A.)

Abstract

Sufficient adhesion between metals and polymers is only to obtain by chemical bonds in the surface layers between metal and the polymer. But also in this case remains mostly sensitivity of the boundary zone against humidity diffusing through the polymer and primary corrosion starting at unprotected parts of the metal. Three deterioration mechanisms are to be observed. The first is a weakening effect in a polymer layer near the metal oxides whose structure differs from the bulk polymer and is influenced by the chemical and physical properties of the surface. This weakening mechanism mostly is reversible. The second mechanism is a slow changing of the oxides by hydration and a diffusing process of parts of the oxides into the polymer without creation of pores. This process is irreversible and influenced by the state of the surface and the chemical properties of the polymer. The third mechanism is a fast deterioration of the oxides by primary corrosion starting at unprotected edges of the metal and sometimes within the compound. In this case, the oxygen concentration plays an important role besides the stability of the oxides and the chemical properties of the polymer. On hand of knowledge about these deterioration mechanisms, different ways of systematical optimization will be discussed.